Rock drill feeding means



Aug. 1o, 1937. E Q GARTIN 2,089,202

i Rovcx DRILL FEEDING MEANS i 3 `Sheets-Shee'l'. l

Filed May l1, 1955 n "HAMM Ik Z f uw m@ m N @w W 4.# $4 f .III WMM w u@.mw ww NN m QN QQ hw www w mm ww Q No@ w @e ww @6% m 1 my I--- 1 lill--Huhn.. -.hlhnlhunuunnuhwuhwnF.unuuuuHLHHHJ a Q IJ U lr um VL,

k. w w n JU Aug. 10, 1937. E. G. GARTIN ROCK DRILL FEED-ING MEANS 5sheets-sheet 2 Filed May ll, 1955 SS n@ l A TTORNE Y .A/ i, n W N.

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Aug. -10, 1937. E. GARTlN 2,089,202

ROCK DRILL FEEDING MEANS Filed May 11, 1955 s sheets-sheet s PatentedAug. 10, 19.37

' STA-r es noci( DRILL FEDING MEANS Elmer G. Gartin, Claremonhfl;assigner to Sullivan Machinery Company', a corporation of fMassachusetts y ivApplijcationMay 11-, 1935, Serialy 21,026,

'2c claims. (el, 1:21.44),

'I'his-invention r'elatest'o :rock drill feeding means, land f moreparticularly" hasv reference Ito improvements inv a pressure; fluidactuated `lfeed.- ing I means for aV hammer vrock drill 'of ftheYmountfed drifterftype;l

v An-object' of -thisinventionhis to provide an improved-rock,drillyfeeding means. Another object i'sto'provide anl improved pressurefluid actuated feeding means for a. rockdrill of the Amounteddriftertype hav-ing embodied .therein 'animproved' direct acting: feedingdevice having a minimum; A"overa-l1 length lconsistent with the totalIengtlr'o feed.; Stillanother-object'of this 'invention' is to providean improved pressurey iluid actuated feedingfmeans'forfa rock drillwherein the overall dimens-ion "of the feeding device remains constantthroughout the-'travelffo'r `feed of therockdrill.' yYet another objectof'vth'is in- 'vention `is to provide' a'n improved Apressure-fluidactuatedl'feedin'g'means having embodied therein improved means 'formaintaining the vactive feed- "ing parts locked-,against movementWheneverzthe feed is renderedxinactive. These andother I'ob'- jectsIvwill, however," subsequently'more full appear.. l.

In the accompanying'drawingsthere-are shown forfpurlposesofillustrati'on onefor'm'and `a modlfica-tion which ftheinventionimayiassume in practicei In theseid'rawings, t i

Figi-1 isa view 'in longitudinal section.- of an illustrativev'embodirnent ofthe improved feeding meansandiUs associated rock drill.f

Fig.2is a ll'iorizon--tal sectionaliview taken su stantially'on'lline21-`2Fof Figsfl' and A5;

Fig.'3 is' ai piani view vof thev improved feeding means with 'the rockdrill removedftherefrom.

Fig; 4' is a cross'sectional View taken substantially on line 4"-4 ofFig. l; with' internal'motor parts'omitted*A l I Fig-l' 5-is a crosssectional view taken v'substantiallyon yline 5 5 of Fig'."1, withinterna-1 motor parts omitted. f Fig. 6 is a viewsirnilar to'Fig. 4showing a modied form of cylinder and piston'structure.

Fig; 7 is across sectional viewftaken substantially on line 1-7-1 ofFigi 1'.

Fig. 8 is' a detail 4sectional view taken on line .s -s of'rig. 7.

Fig. 9 is a detail sectional view taken on line Q- S-cfFig?.

VFig; v10 is a detail sectional view .takenv on line I-Il--III of Fig;7with-the feed control' valve in ardiiferentfpositionff 4 .Fig,. 11visadetail sectional view villustrating the automatic control valve.

In this illustrative'embodimentof the inventionthere 'is shown ardriftertype hammer rock drillgenerally designated I; conventionalin form, and'comprising a cylinder 2 having a piston chamberv 3 containing areciprocable Vhammer pistonv for delivering impact blows to the shank ofadrillsteel 4; The -motor cylinder 2V has a vrear head 5 anda frontchuck housing yIi, the f1.0

latter suitably supporting the chuck-for the 'drill steel4'and-,the-elements 2, 5, and 6 maintained iii-assembled relation byksuitable side rods 1. -As is `usual in rock drills'of the mountedvdrifter type,y themotor cylinder 2-has formed on its bottom-surfaceparallel'guides 8;,8-slidably mounted 'in longitudinal guideways 9, 9formed onthe upper vsurface --of thefeed cylinder I0 of the improvedAfeedingdeVice generally ydesignated I'I. The guidewaysy 9 are formed byupper plates I2 4'and a-nl intermediate plate- I3 havingf a longitudinalvguiding groove I4 forming the guideways, the plates-I2 and I3 beingsecured in assembled relation with respect to side flanges integral with.the feedcylinder I0 by means of bolts I5. The 5platef-I3 lhas la planebottom surfacev I6 and has -symmetricallywith its axis a=closedslot I'Iextending' substantially its full length. Through this slotA aldepending driving Aprojection herein :inV the-form of a stanchion I8.formedk integral (30 With, lthe 'lower portion of the chuck housing 64;extends.into'engagement Withva feed piston I9,

jthe latter herein of rectangular cross section, re-

ciprocable in a 'correspondingly shaped bore 20 nal slot `Il ismaintained sealed irrespective `of the, positionof the -feedpiston withrespect to the: feed cylinder by meansof an inner endlesssealing-strip2| herein in the form of a flat metallic -ribbon preferably composed `ofspring steel, guided-between thel bottom surface I6 of the plate rI3andledge-like shoulders 22 formed lon the-feed'cylinderflll. vThestanchion I8 extends through an opening 23 formedin this sealing stripfor securing-the strip to thel feed -piston and this strip lat theloppositeendsof the feed cylinder is guided within* arcuate recesses 24formed in end heads 25 of the feed cylinder II). This flexible strippassesaround the curved inner` surfaces ofthe recesses 24 and the bottomlongitudinalportion thereof extends longitudinally of the feed cylinderin parallel relation with its intermediate upper portion through aylongitudinal slot 1liV formed in the bottom surface Aof the feedcylinder I0. The stanchion.- I8 also passes through an opening 2'Iformed in an outer endless dust strip 28 similar to the strip 2| but ofsubstantially less width, as shown in Fig. 4. 'Ihis dust strip is guidedon the outer plane surface I4 of the plate I3 and the cylinder heads 25are formed with arcuate recesses 29 in which this strip at the ends ofthe feed cylinder is guided, the bottom longitudinal portion of the-duststrip underlying the bottom portion of the sealing strip 2| and likewiseguided at the bottom of the feed cylinder. The bottom plane surface ofthe plate I3 has formed therein series of packing, lubricating andbalancing grooves 3l) running parallel with the closed slot Il, thesegrooves beingindividually made discontinuous vfor a purpose `to be l.

later explained. Secured between the heads 25 and the ends of the feedcylinder are plates 3| having secured thereto as by screws suitable cuppackings 32, while secured to the opposite faces.

of the feed piston by screws 33 are similarrcup packings 34.'Ihe'packingfs32 sealingly engage the inner walls of the -feedv cylinderbore and the inner surface of theinner sealingstrip 2| to preventleakage of pressure fluid from the ends of the feed cylinder bore pastthe end plates, while the packings 34 sealingly engage the walls of thecylinder bore and the inner surface of the sealing strip to preventleakage of pressure fluid from the ends of the cylinder bore past thefeed piston.-v Secured to the bottom surface of the feed cylinder I0 inYany suitable manner, as by welding, and enclosing the outer side of theslot 26, is a bottom plate 35 having formed integral with the bottomlportion `thereof l a :supporting trunnion36. The inner' sealing strip isslightly widerthan'the width'of cylinder bore, while the sides ofvtheouter dust strip overlie the edges of thevslot -I'I so that thesestrips always maintain the "upper side ofthe feed piston and the upperside of the slot VI 'I continuously sealed irrespective ofthe positionof-the feed piston within the feed cylinder bore, and the guiding meansfor the strips provide freedom for travel of the strips at either edgethereof, although guiding the same rmly. The curved recesses of theheads 25 are so formed as to constrain the strips to bend back uponthemselves in an easy curve so that their ends lie between the base wallof the cylinder in the groove 26 and a cooperating bottom groove 3'Iin'which the outer dust strip is guided. To provide for directness ofdrive between the stanchion I8 of the rock drill and the feedrpiston I9both as totrue axiality vof piston thrust and in order to makeallowances for slackness between the drill guide elements 8, |2 and I3,a piston pin 38 is'used as one element of the con- Vnecting mechanismbetween the rock drill and the feedpiston, this -pin being free torotate transversely of the piston inthe bore 39 and in turn piercedtransverselyat '40 to receive slidably Ithe stanchion I8. Thecombination of stanchion androtatable piston pin provides a desirableuniversality lo'ffactionA between the stanchion and the piston' guides..In action'the reactance of the feeding pressure is Vdirectly againstthefeed piston and so to therockdrill, so the only stress in the sealingstrip is that' imposed by its own friction when'subjected to pressure inthe cylinder bore, crowding it against the plane surface I6 of theintermediate plate I3, plus a negligible load due to bridging of theslot II. Obviously, its

i friction load willvarydirectly with the length of kthe strip'exposedto' pressure wall. Such being thecase, it isg'necessary to entertain-adiminishing feeding effort or else avoid the loss'by bal-V ancing thepressure on the strip by the grooves 30. Were these grooves to be freelycommunicative from end to end of the guide plate I3, pressure reachingthem due to leakage from the feed cylinder around the strip edges, wouldtravel beyond the pressure area on one side of the piston to the zone ofless pressure on the opposite, nonfeeding side of the pistonandsovescape without lessening the friction creating pressure-betweenthe plate I3 and the sliding sealing strip; hence the series of grooves30 are formed discontinuous with a series of partitions or obstructionsleft betweenthe grooves which become effective to stop this longitudinalflow v.from one side of the feed .piston to the other, provided theirlength is less than the distancev between the opposite faces of the feedpiston. The staunchness of such a construction against pressure fluidleakage is primarilyone of workmanship, since the interstice necessarilyleftY between the edge of the strip and its'guideway can 'not bedefinitelyv packed. 5 'Ihe -usu'aldifficulty of packing a right-angledcorner,

necessarily in this case without fillet, ofcourse is present, but'themoulding of packing has progressed to a point where these difficultiesunder modern conditions are vastly 'less than heretofore. The'operatingnecessity for some leakage from such a feed cylinder,v if even, forwardurge is to be achieved, isa favorablecircumstance. The probability ofslight leakage is therefore entertainable with equanimity. For thesealing of the strip against the guide base I3, excellentconditionsobtaimand the necessityfor a flexible strip in order to vmakethe end turns, materially enhances the probability of securingstaunchness to the slot through which ythe connection to the rock drillpasses. f Y l f Suitable pressure rfluid passages "controlled by valvemechanism to be later described, are drilled in the rear head 5 and themotor cylinder'f'2,fand 40 these passages communicate with `parallelpassages 43 and formed in thevstanchion I8,l and the latterpassages'communicate tothe diverse faces 'of .the feed piston I9 throughthe medium of spring-pressed thimbles 45'sealed against op.-

posed faces of the stanchion and conduits 46 and 41, eventually issuingto the cylinder bore Ythrough drilled holes in the packing attachmentscrews 33.

Provision has also been made for retaining the rock drill in anyposition `with respect `to the guideways of the feeding device whenpressure fluid is unavailable inthe feedcylinder. This mechanismcomprises a shoe 50 bearing upon the returned sections of` the sealingand dust strips which it traps against the base wall ofthe feed 55cylinder by influence of a stout spring 5I. The effort of thespringtransmitted through a toggle 52 tothe shoe 5|1 aggregates a thrustnormal -to the cylinder base Wall and so to the strips sufficient toprovide friction capable of support .ing the weight ofthe rock drill invertical position. The pressure of the spring 5I is neutralized whenpressure fluid is available in the feed cylinder by theopposingpressure-within the lcylinder and piston .combination 53,sufficient inarea to live pressure between the feed cylinder'ends but fCII- the brake shoe when the piston 53' is moved toward the right inFig. 1 by the coiled spring 5I, that is, when both ends 'of the feedcylinder are connected to exhaust. v"-Ihe'brake shoe and toggle arepreferably slotted at vtheir pivotal connection with the cross pin 51`to permit'free bodily -movement of the brake shoe and pivotal movementof the toggle. The automatic valve meansV 54', as

l shown most clearly in Fig.11, comprises a doubleended valve 55 guidedfor reciprocation in a bore formedl in the cylinder base and normallyvheld in its centered position by'oppositely acting coiled springs 56and 55. The opposite yends of the valve bore are connected lthroughpassages 51 and 51 With the opposite ends of the 'feed cylinder bore atthe opposite sides of thefeed piston, so that when pressure uid issupplied through one passage to one end of the feed cylinder bore,pressure fluid is simultaneously supplied to one end of the .valve 55 tomove the valve against the pressure of the opposing spring to cut offcommunication of the other end of the feed cylinder bore With said otherpassage. Also )communicating With the valve-bore are passages .58 and 58connected by a passage 59 with the passage 54 leading to the bore Aofthe cylinder containing the piston 53'; and these passages 58 and 58'are maintained in communication with the passages -51 and 51y When' thevalve 55 is in its centered position .shownin Fig. l1. When the valve 55ismoved toone vend or the other of -its bore by thepressurefluid in oneof the passages 51, 51', pressure fluid is supplied through one of thepassages 58, 58 to the passage 59, and thence to the'passage 54'toeffect'release of the brake, While communication of 'the passages 58, 58With the other of the passages 51, 51 iscut off by the valve. 'It willthus be yseen that Whenever pressure fluid is supplied to the feedcylinder, the brake is maintained released bythe pressure in the passage54 acting on the brake piston; and when the yfeed `cylinder is connectedto exhaust, the brake isautomatically applied by the coiled spring 5I.

In Fig. 6 is shown an alternate form of the cylinder andpiston'structure.l Herein the guide- Ways Sfor receiving the guides 8 on'the `rock drill are formed by upper plates 50, and an intermediateplate 6| ybolted to one side of a'feed cylinder 62 herein of cylindricalform, and a support of normal characterA is attached `midway of thecylinder length at 53. Reciprocable inthe circular bore 64 of kthis feedcylinder is a cylindrical feed piston 55 carrying annular packingsinstead of the packings of vrectangular 'shape shown in Fig. v 2. Thestanchion for directly connecting the rock drill to the feed pistonisindicated at 56, the stanchion entering a similar piston-pin-arrangementwith pressure fluid distribution in general as above described.` Thepiston, however, instead of being rectangular is circular, and circularpackings maybe used both at the piston and at :the end heads. Thecylinder vWall adjacent to and symmetrical with theY closed slot 6i,through which thestanchion 56 'reaches the piston, is breached to take.a vcurved sealing strip Z68, 'the concavity of Whichfis aniarc of thecylinder-size selected. End return `means isv made asin Fig. l exceptthat the origin of the -return bend is further removed from lthecylinder head plates in order to permit the change g5 'in form kfromarcuate to fiat section on the part 'of the strip inseparable fromreturn bending of 'such a form. Protection means for the inactive*portion of the strip lying beneath the cylinder is achieved' bybuilt-up construction, and manu- 5:50

facture of the strip in this specic form Vis now Vavvell-knovvn andclosely controlled art. A familiar example of such a strip and theAnature Vof a return bend made in it Vis furnished by the type of steelmeasure coiled interiorly of a cir-'15 cular container to be found inalmost .every mechanically interested establishment. A marked detaileddifference between the two designs, apart -from the circularity oi' thelatter, is Worthy Aof note. In the case of the flat strip, it is neces-520 `sary vto snare its edges between the guide base I3 and the cylinderbody to avoid sagging on the non-feeding side. The strip in this case ispositively guided and sagging can only result from bending transverselyof the strip. In-the225 Case of the circular piston, however, theinherently stiff, arched form of the strip removes this fear, and it isconsequently unnecessary to .provide snaring for the strip edges. 'Ihearched strip is also practical in a narrower width "thaniiO the flatstrip; on accountof this lack of necessity for support, edge friction'is consequently less. The packings, sealing and duststrips and thestrip-receiving passages are the 'same as those above described, withthe exception that they 35 are curved to accommodate a circular feedcylinder; Wherefore further illustration of details is? unnecessary. p f

Now referring to the valve mechanism and fluid distributing passagesVfor supplying pressure 1:40

fluid to the passages i3V and 44 heretofore de scribed, as clearly shownin Figs. '7 to 10 inclusive, it'will be noted thereis illustrated as onepossible .feed control means a device more Vfully illustratedanddisclosed in Patent No. 2,015,678f1i15 granted Oct. l, 1935. Itlvvill be observed vthat pressure fluid flows from ay suitable source ofsupply through an inlet connection 10 into a 'bore 1I formed centrallyin the main throttle valve 12 of the drilling motor, the valve rotatably(50 mounted in the rear head 5 of the rock drill. This valve is formedwith an axial bore 13 communicating with the bore 1I, and is traversedby a radial passage 14 (see Fig. 8) connecting the bore 1I with acircumferentially-extending.x55 groove 15 on the exterior valveperiphery. Also formed on the exterior valvel periphery lin the sametransverse plane as the groove 15 is a circumferentially extendinggroove 15. Formed on the exterior periphery of the* valve, as shoWno-oin Fig. 9, are circumferentially-extending grooves 11 and 18, the formercommunicating with the axial boreV 13 in the valve through a radialpas-- sage 19. Arranged transversely of the rear head 5 of the rockdrill is a bore 85 having mounted35 therein a rotary feed control valve8|: Connecting the throttle valve bore With the bore of the feed controlvalve and lying inthe planes of the grooves 15, 16 and 11, 18 areparallel passages 83 and S2, while lying in the same planes170 as thesepassages and grooves, as shown in Figs. '8 and 9, are exhaust ports and84 respectively. The passages 82 and 8'3 are communicable through thefeed control valveY Si with parallel passages 8S and 81, respectively,formed'fi'nthe-' motor cylinder and communicating with `the feed vsupplypassages 43 and 44 respectively formed rin the stanchion I8 andcommunicating with the opposite ends of the cylinder bore at theopposite sides of the feed piston. As shown, the feed control valve 8|is traversed by a passage 88 and a communicating right angle passage 89,the latter opening at one end into a longitudinally extending groove inthe periphery of the valve. When the valve is in the position shown inFigs. 7 and 9, passages 89 and 88 and groove |00 connect the passage 82with the forward feed passage 86. The valve 8| is also traversed by apassage 90 which is communicable with an axial passage 9|, in turncommunicable through a radial passage 92 with the passage 83, and adiametric passage 93 with the reverse feed passage 81. As shown in Fig.10, arranged parallel with the valve bore 80 is a passage 94communicable, when the valve 8| is in the position shown in Fig. 9,through a passage 95, with the passage 88 in the feed control valve.When the valve is in the position shown in Fig. 10 the passage 94 isconnected through a passage 96 and the transverse passage 90 in thevalve 8| With a vent port 91. The valve 8| is also traversed by a radialpassage 98 communicating with the axial passage 9|, and when the valveis in the position shown in Fig. 10, connects the passage 81 to exhaustthrough the vent port 91. The valve 8| is also provided with alongitudinal groove 99 on its exterior periphery, and this groove iscommunicable with the passage 82 and connects with the passage 90, oneend of which opens into the end of said groove. Also formed on the valve8| is. the longitudinal groove |00, above mentioned,` into which thepassage 88 opens and which is communicable in one position of the valvewith exhaust port 91.

From the foregoing description it will be evi.- dent that when thethrottle valve 12 and feed control valve 8| are in the position shown inFig. 7, pressure fluid may flow through the inlet connection 10 to thevalve bores 1|, 13, through radial passage 19, passage 82, passages 89and 88 in the valve 8|, passages 95, 94 and the forward vfeed passage 86which communicates with the feed cylinder bore at the rear side of thefeed piston. At the same time the forward end of the feed cylinder boreis connected to exhaust through the reverse feed passage 81, andpassages 93, 9| and 92 in the valve 8| passage 83, groove 16 and vent85, and as a result the rock drill is fed forwardly along the feedcylinder. When the throttle valve is rotated into its reverse feedingposition, pressure fluid may flow through radial passage 14, groove 15,passage 83, through the passages in the valve 8| and reverse feedpassage 81, which communicates with the feed cylinder bore at theforward side of the feed piston, while the feed cylinder bore at therear side of the feed piston is simultaneously connected to exhaustthrough passage 88, through the passages in the valves 8| and 12, andthe vent passage 84, and as a result the rock drill is fedrearwardlyalong the feed cylinder. The forward feed passage 88 may beconnected to exhaust at will during the forward feeding operation simplyby rotating the feed control valve 8| to the position shown in Fig. l0,thereby connecting the passage 86 to exhaust through passages 94, 95,groove 99, and passages 90 and 91. When the valve 8| is in this positionthe flow of pressure fluid to the passage 8B is cut off by thefvalve 8|.If it is desired to connect the reversefeed passage l81 to atmosphereduring the reverse feeding operation, the valve 8| may be turned toconnect the passage 81 with the passage 98, lbore 9|, passage 90 andvent port 91.` At this time the communication between the supply passage83 and the passage 81 is cut off by the valve'8l. A quick reverse duringfeed in either direction may be obtained by other adjustments of thevalve 8| but as this is fully described in the patent mentioned, and asthis feed control valve mechanism does not specifically lenter into thisinvention, being merely illustrative of any suitable control, furtherdescription of its structure and mode of use is herein consideredunnecessary.

As a result of this invention it will be noted that an improved rockdrill feeding mechanism is provided whereby a direct feeding action istransmitted `to the rock drill, while the overall dimensions thereof aremaintained at a minimum. It will further be noted that an improvedpneumatic feeding mechanism is provided of the cylinder and piston type,wherein the feed piston is rconnected directly to the rock drill,thereby to attain a direct feeding action, and having embodied thereinimproved sealing means whereby the connection between the rock drill andfeed piston is always maintained sealed. It will further be evident thatthe improved feeding mechanism is not only extremely compact in overalldimensions but is also of an extremely simple and rugged construction,all complicated connections between the power feeding element and therock drill having been eliminated. These and other uses and advantagesof the improved feeding mechanisml will be clearly apparent to thoseskilled in the art.

While I have in this application specifically described one form whichmy invention may assume -i`n` practice, and a certain modificationthereof, it will be understood that this form of the same is shown forpurposes of illustration, and that the invention may be further modifiedand embodied in various other forms without departing from its spirit orthe scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is:

1. In a rock drill feeding mechanism, a feed cylinder having a bore anda longitudinal slot extending substantially coextensively with saidbore, a feed piston reciprocable in said feed cylinder bore, meansextending through said slot into engagement with said feed piston andadapted for connection to a rock drill, means movable with said feedpiston for always maintaining said slot sealed irrespective of theposition of said feed piston in said cylinder bore, and means associatedwith said sealing means and movable withv said feed piston for providnga dust seal for said slot.

2. In a rockdrill feeding mechanism, a feed cylvinder having a bore and'a longitudinal slot extending substantially coextensively with saidbore, a feed piston reciprocable in said bore, means extending throughsaid slot into engagement with said feed piston and adapted forconnection to a rock drill, means movable with said feed piston foralways maintaining said slot sealed regardless of the position of thefeed piston in said cylinder bore, means for supplying pressure fluid tosaid cylinder to effect actuation of said feed piston, and means forlocking said feed piston against movement in said cylinder boreincluding a feed piston locking device and means operative when saidJsup'ltllyV of pressure vfluidto tsaid -c'ylindenr is discontinuedf'forautomatically operating said locking Vdevice 'to lockV vsaid. feed`piston lagainst movementin said cylinder bore. l 1

3; In a rock .drill feeding mechanism, a feed cylinder havingfa bore andalongitudin'al IIslot extending --substantially 'coextensively with"said bore,l a feed piston reciprocable insaid boregmeans 'extendingthroughl saidslot into engagement'with said feed piston and adaptedforconnection to a rock drill, means movable'v'vith 'said feedpiston-forI always maintaining said slotsealed regardL less of the position of'thefeed piston in saidlcylinder. bore; meansfor lsupplying pressurefuidto saidcylinder toieifect actuation of said feed-pis- -ton, and meansforlockingsaid feed pistonragainst .movement in saidy cylinder. boreincluding lock'- .in'g means engageable with said sealing "means,

yfor connecting the rock` drill directly to said-feed piston, meansmovable-by said feed piston for always maintaining said slot Fsealedregardless of the position of saidffeed piston in said cylinder bore,and means associated with said lsealing Vmeans for :providing a dustseal for fsaid' sealing means toprotect the same for 'its full area.-

In Ya .rock drilling SmeChaniSm, .ai feed 'cylinder having-1a bore,a'lgudeway. on which a'rock drill is slidablyfg'uided-andya'flongitudinal'slot extending subs'tantially..coextensivelyA with'said cylinder bore, a'feedpiston lrecipocalolein said cylinder bore,meansftextendi'ngthrough said slot `for connecting the rockdrilldirectlyt'o/fs'aid,I feed piston, and. means for y'automatically 'locking's'aidfeed lpiston against 4movement in said'cylinder bore when the feeding'operation"isfinterrupted.`

l(i, In a: rock drilling mechanism, a feedcylird'er having-a bore, a.guideway on Whichfa ro'ck drill is slidably guided vand a longitudinalslot extending substantially coextensively'with 'saidcyli'nderbora `afeed piston reciprocable in. said cylinder bore, means 'extendingthrough Vsaid slot for`connectin'g thefr'ock drill directlyto said feedpiston, means for locking said feed piston against movement in saidcylinder bore, means for automatically operating said locking means forlocking said feed piston against movement in said cylinder bore when thefeeding operation is interrupted, and means for automatically releasingsaid locking means when the feeding operation is effected.

7. In a rock drilling mechanism, a feed cylinder having a bore, alongitudinal guideway along which a rock drill is slidably guided and alongitudinal slot extending substantially coextensively with saidcylinder bore, a feed piston reciprocable in said cylinder bore, meansextending through said slot for connecting the rock drill directly tosaid feed piston and embodying a pivotal stanchion connection, andsealing means for said slot for maintaining said slot sealedirrespective of the position of said feed piston in said cylinder bore.

8. In a rock drill feeding mechanism, a feed cylinder having a bore anda longitudinal slot extending substantially coextensively with saidhor.e,y.axfeed piston reciprocable 'in-*said feed"cylinder;'bore;.m'eans extending through said slot into engagement'with saidfeed piston andadapt- 4ed for connection to arock drill, aflexible seallingstrip 4'movable vbysaid pistonfor alwaysmaintainingsaid slot sealed-irrespective of the position ofsaidl feed pistonin saidcylinderbore,;and a flexible dust strip, lfor always-maintaining 'saidsealing strip sealed-against access of dust thereto.

9.1Infayrock drillfeeding mechanism,` in combination, afeeding motor-comprising relatively `'reciprocable ffeed cylinder and pisto 11elements, 'mean'sfor supplying pressure fluid tof said feeding motor ltoveffect relative reciprocation between said ffeedingelements, andlocking means for locking 'said feeding elements againstrelativereciprocation, said locking means including a locking devicefor-saidfeeding elements :and mechanically operated', pressure fluid releasedmeans automatically operative When'the supply of pressure fluid :to`said feeding motor is; discontinued, for causing said locking deviceYtoilock'said feeding elements against relative reciprocation, and saidflocking.: means being released lby pressure fluid againstV the actionof the mechanical operating means. i Y i. 10.'In arockdrillfeedingmechanism, a feeding 'motor `comprising'relatively reciprocable feedcylinder and piston elements, means for supplying: pressure fluidrtosaid feeding motor to effect relative 'reciprocation' betweenk saidfeeding elements, and -means for locking A.said feeding' elementsagainstrelative reciprocation, saidlocking means including a lockingdevice..for.- said feeding elements andmeans controlledf'by the pressurein saidfeeding'motor and automatically operative when the supply ofpressure fluid to said feeding motor is'discontinue'd, for causing -saidlocking device to :lock `.said feeding elements against relativereciprocation.

11. In'a rock drilllfeeding mechanism, in combination, av feed'cylinderAhaving a bore and "a rlongitudinal slot Iextending :substantially'coextensively with said bore, a feed piston reciprocable in said bore;means vextending through said'slot into engagement .with said feedpiston and'adapted for connection to a rock drill, means movable withAsaid 'feedpiston for always maintaining said slot sealed regardlessofthe position 'of the feed piston insaid cylinder bore, 'means for:supplying pressure fluid to said feed Vcylinder to effectfactuation ofsaid feed piston, and locking means'A for locking said feed pistonagainst movement in the cylinder bore, said locking means including afeed piston locking device and means controlled by the pressure in saidfeed cylinder and automatically operative When said supply of pressurefluid to said cylinder is discontinued, for causing said locking deviceto lock said feed piston against movement in said cylinder bore.

12. In a rock drill feeding mechanism, in combination, a feed cylinderhaving a bore and a longitudinal slot extending substantiallycoextensively with said bore, a feed piston reciprocable means-engaging,locking device and meanscontrolled by the pressure in said feed cylinderand automatically operative when said supply of pressure fluid-to saidcylinder is discontinued, for causing said locking device to lock said`feed piston against movement in said cylinder bore.

13. In a rock drill feeding mechanism, in combination, a feed cylinderhaving a bore and a longitudinal slot extending substantiallycoextensively with said bore, a feed piston reciprocable in said feedcylinder bore, means movable with said feed piston for alwaysmaintaining said slot sealed irrespective of the position of said feedpiston in said cylinderbore, and means associated with said sealingmeans and movable with said feed piston for providing a continuous dustseal for said sealing means.

14. In a rock drilling mechanism, in combination, a support having alongitudinal guideway, a rock drill slidably guided on said guideway,said support providing a feed cylinder having a bore extendinglongitudinally of the support guideways, said feed cylinder having awall thereof open substantially along the length of the cylinder bore,means extending through said longitudinal opening for connecting therockdrill directly to said feed piston, means movable with said feedpiston for continuously maintaining said longi-v tudinal opening closedirrespective of the position of said feed piston with respect to thefeed cylinder, and means associated with said closure means forcontinuously providing a dust seal for said sealing means to protect thesame for. its full area. Y

15. In a rock drill feeding mechanism, a feed cylinder having alongitudinal slot substantially coextensive with its bore, a feed pistonreciprocable in said cylinder bore and to which a rock drill to be fedis adapted to be directly connected, a flexible sealing strip movablewith said'feed piston for always maintaining said slot sealed, and aflexible dust strip movable with said feed piston for always providing adust closure for said sealing strip.

16. In a rock drilling mechanism, a feed cylinder having a longitudinalseal extending substantially coextensively with its bore, a feed pistonreciprocable in said bore and adapted for connection with a rock drill,means movable upon 50 movement of said feed piston for alwaysmaintaining said slot sealed, and means movable upon movement of saidfeed piston for always.- providing a dust closure for said sealingmeans.

viding a longitudinal guideway,

` 1'7. In va' rockdrilling mechanism, a feed cylinder having alongitudinal slot extending substantially coextensively with its bore,Va feed piston reciprocable in said bore and adapted for connection lwitha rock drill, an endless flexible sealing strip secured to said feedpiston for always maintainingl said slot tightly sealed, and an endlessflexible dust strip secured to said feed piston for always providing adust closure for said sealing strip.

18. In a rock drilling mechanism, means proa rock drill guided on saidguideway; feeding means including relatively reciprocable vcylinder andpiston elements arranged parallel with said guideway, and a connectionbetween the reciprocable feeding element and the rock drill comprising astanchion secured to a part of the drill, and a block pivotallyconnected with the reciprocable feeding element and having a socket forreceiving said stanchion. Y

19. In a rock drilling mechanism, means providing a longitudinalguideway, a rock drill guided onsaid guideway, feedingmeans includingrelatively reciprocable cylinder and piston elements arranged parallelwith Vsaid guideway, and a connection between the reciprocable feedingelement and the rock drill comprising a stanchion secured to a part ofthe drill and a. block pivotally connected with the reciprocable feedingelement on an axis arranged transversely to the direction of feed, saidblock having a bore arranged at right angles to said transverse axis forreceiving said stanchion.Y

20. In a rock .drilling mechanism, means providing a longitudinalguideway, a rock drill guided on said guideway, feeding means includingrelatively reciprocable cylinder and piston elements arranged parallelwith said guideway and a connection between thefreciprocable feedingelement and the rock drill comprising a stanchion secured to a part ofthe drill and a block pivotally connected with the reciprocable feedingelement and having a socket Yfor pivotally receiving said stanchiomandmeans for supplying pressure fluid to said cylinder element to effectrelative reciprocation of said feeding element including fluid supplypassages in said stanchion and said block, andmeans -for maintainingcommunication between said` passages regardless of the .relative pivotedposition of said block relative to said stanchion and the reciprocablefeeding element.

, ELMER G. GARTIN.

